Regulator for dynamo-electric machines and motors



3 Sheets-Sheet 1.

(No Model.)

R. H. MATHER.

REGULATOR ECR DYNAMC ELECTRIC MACHINES AND MCTCRS.

Patented Aug. 25, 1885.A

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(No Model.) 3 Sheets-Sheet2.

R. H. MATHBR. REGULATOR FOR DYNAMO ELECTRIC MACHINES AND MOTORS. No. 324,862.

Patented Aug. 25, 1885.

@M/@WMA (No Model.) 3 Sheets-Sheet 3.

R. H. MATHER.

REGULATOR EOE DYNAMO ELECTRIC MACHINES AND MOTORS. NO. 324,862. Patented Aug. 25, 1885..

, Wfl/Am sses: Inventor:

' C55? @Mw am@ mmm @WMZ UNITED STATES RICHARD H. MATHER, OF

PATENT OFFICE.

YVINDSOR, CONNECTICUT.

SPECIFICATION forming part of Letters Patent No. 324,862, dated August 25,1885.

Application {ifed October Q3, 18S-l. (No model.)

To all whom it may concern:

Be it known that I, RICHARD H. MATHER, a citixen ofthe United States, residing in the town ol' NVintlsor, county of Hartford, and State of Connecticut, have invented certain new and useful 'Improvements in Dynamo- Electric b'lachines, ol' which the following is a full, clear, and exact description, such as will enable others skilled in the art to which it appertains to make and use the same, referencebeing had to the accompanying drawings, which form a part of this specification.

My invention relates to the construction of dynamo-electric machines of the classes commonly known as shunt-dynamos, magneto-dynamos, and separately-excited dynamos.77

The object of my invention is to render dynamoelectric machines of the specified classes self -regulating in such a sense that, with a constant speed of driving, and with a constant position of the brushes, any such machine will maintain a constant potential regardless of variations of resistance in the working-circuitin other words, it is the object of my invention to prevent the occurrence of sparking at the commutator without any change in the position of the brushes, and at the same time to producea constant electromotive force regardless of Variations of resistance in the main circuit, a result which is particularly desirable in incandescent lighting and in the electric deposition of metals. rlhe principal. feature of the invention by means of which these objects are secured consists of an electro-magnet, or a number of electro-magnets, as the case may be, in addition to or in extension of the ordinary fieldmagnet of such a machine, which additional magnet may appropriately be termed a regulating vfield-magnet,77 from the fact that in the operation of a dynamo embodying` the present invention this magnet regulates the intensity of the magnetic iield in which the armature revolves, as against the effect of nnequal variations of intensity in the relative magnetization ofthe held-.magnet and armature ofthe machine, as hereinafter explained.

I proceed to point out the best mode in which I have contemplated applying my invention.

Figure l is a diagrammatic representation of my invention as embodied in a dynamo electric generator provided with a drum armature and shunt-wound field magnet, and having incandescentlamps in the main circuit. Fig. 2 is a diagrammaticrepresentation of my invention as applied to a dynamo-electric generator which is provided with a ring-armature, and with a shunt-wound field-magnet with incandescent lamps inthe main circuit. Fig. 3 is a diagrammatic representation of my invention embodied in a multiple polar electric motorin circuitv with a generator and having a shunt- Wound held-magnet.

Inthese drawings, andv with special reference to Fig. l, F is the held-magnet proper, the particular form of which is unimportant in this connection. The north and south poles ofthe held-magnet. are lettered, respectively, Naud S. The corresponding poles of the armature are lettered, respectively, a and s. The arrows indicate the direction oli the current. The armature A is provided with commutator c and brushes b b in the usual manner, as shown. As it is unnecessary in View of the mode of operation ofthis invention to adjust the brushes during the operation of the machine, as has heretofore been practiced, for the purpose of preventing sparking, the brushes b I) are set in a permanent position, indicated in the drawings, and determined in the manner hereinafter explained.

R is the regulating field-magnet, which conA sists of a core of soft iron wound as an, electromaguet and having north and south poles, which are lettered, respectively, aand s. The figure presents an edge View of the magnet R, whose core should preferably be in the form of a solid bar or plate, and whose size is determined in the manner hereinafter explained. This magnet may conveniently be suspended in a perpendicular position midway between the arms of the field-magnet, as shown. The same should be placed in a fixed position, such that one of its poles-in Fig. Il, the north pole, a-shall be in close proximity to the armature A, as shown. rlhe best attachment of the magnet R is by bolting the same to the field-magnet proper in the position mentioned, as shown in the drawings. rihe position of the magnet R over the armature, as in i Fig. l, possesses an incidental advantage in l the circumstance that in the operation ol' the machine the magnet It, placed in that position, tends to lift the armature A, and so reduces friction at the bearings.

Iremising that the helix of the magnet R is of coarse wire, and is in the main circuit, as shown, I proceed to point out more particularly the construction of this magnet both in respect of the size of its core and in respect of the size and length of wire contained in its helix.

In the construction of any particular dynamo embodying the present invention I determine these particulars in the following` manner: Having completed the dynamo as to all parts thereof, except the regulating-magnet and the adjustments dependent thereon, I run the machine without this magnet at such speed as is necessary to produce the desired electromotive force with a minimum of work in ci rcuit. The work to be done may be assumed to be the operating of ,incandescent lamps, on which assumption I run the generator at such speed as will bring a single light to the normal brilliancy, and place the brushes in such a position as will prevent sparking when but a single lamp is in operation. This determines the normal speed ofthe machine. Then I assume a regulatingmagnet core, which is of convenient length, and is supposed to contain a sufficient quantity of iron to produce, when duly magnetized, the desired degree of regulation. This necessary quantity of iron will be found to vary in different machines inversely as their comparative external and internal resistances. Next I wind upon the assumed regulating-magnet core such a quantity of wire of a size selected for the purpose as is sufficient, when wound upon said core, and when placed in the main circuit with the maximum number of lights which the machine is designed to operate, to produce in said core the necessary degree of magnetization. The wire which istaken l'orthis purpose should beso large as not to become heated during the operation ofthe machine, and the degree of magnetization here called for is such that when the maximum number of lights is in circuit the magnet R approaches saturation, yet not so far as to prevent a practically uniform variation in that magnetization proportionate to the variations in the electric current producing the same whenever the number of lights in actual operation is diminished. Then placing in the workingcircuit ofthe machine the maximum number of lamps which the same is designed to operate, and fixing the regulatingmagnet in position, wound and connected as described, I run the machine at norma-l speed and observe the result. If the lights are too bright I diminishr the power ofthe regulatingmagnet by removing some of the iron from its core, and if too dim I increase the power of this magnet by increasing its mass until the standard brilliancy is attained. This operation determines with a fair degree ol" accuracy the size of the regulating-magnet core and the amount of wire in its helix. If a greater degrec of accuracy is desired, the same process may be repeated by assuming at the outset the rcgulatiiig-magnet core already ascert ai ucd as above. I place the brushes in such a position that no sparking will occur when the maximum number of lights is in operation. By this meansthc comnmtatorsegmcnis which are at any particular time in contact with the brushes are those whose corresponding armature-coils are at the same time beginning to pass under the influence ofthe regalati iig-niagnet. This fixes the permanent position ofthe brushes. The remaining features ofcoustruction involved in this invention, as well as the appropriate connections, will sufficiently appear from the drawings and from the mode of operation, as hereinafter explained.

The mode of operation which results from the foregoing construction is that of a cour bined series and shunt dynamo, iu which the constant lead of a series-machine and the selfregulating qualities of a shunt-machine are united. lt has been the common fate of those shuntunachines which have hitherto been dcvised for the purpose of securing a constant lead, to opera-te more or less impertectly by reason ot' their failure to produce a constant neutral point or a constant diameter ol' columutation in the armature. In such machines this defect is due to the fact that the tieldmagnet and armature are unequally and disproportionately affected as to degree of mag netization by variations of resistance in the main circuit. This inequality is apparent from the fact that in the operation of such machines the maximum range of variation in the intensity of magnetization in the tieldmagnet does not commonly exceed ten percent'. of its minimum normal strength, while the corresponding range of variation in the magnetization of the armature commonly exceeds two thousand per cent. of its minimum nor mal strength, and this defect, which is particularly conspicuous in those machines in which a superior construction has been sought to be gained through diminished range of variation in the leld-magnet, does not altogether disappear, however powerful the construction of the field-magnet and however weak the armature may be. It has also been a defect common to those dynamos which have been designed to secure a constant electro-motive force by means of a compound winding of the fieldauagnet that the same have required for their successful operation a certain critical speed of driving. These defects are remedied by the present invention in the following manner:

It follows from the described construction that the intensity of the magnetic field in which the armature revolves is variable, according to the number of lights or other units of resistance in the main circuit, in a manner which is the effect of the combined operation ot' the field-magnet proper and of the regulating-magnet I). The field-efforce when most reduced is so weak that a single lamp when CIJ placed in circuit will not receive an excessive or insufficient current, and when most increased is so strong that the i'naximum number of lamps when placed in circuit will receive so much current as they require for standard brightness, and no more; and when affected by said magnets to any intermediate degree the intensity of the magnetic 'lield is such that the intermediate number of lamps producing` that varied effect will receive so much current as is necessary to bring those lamps to standard brightness, and no more.

This practical result in the operation ofthe machine may be theoretically explained as follows: The machine being constructed and adjusted as already described, and the maximum number of lights being thereby brought to standard brightness, then il' any number less than all of those lights be turned out, the electro-motive force of the machine tends to increase by reason ot' the increase of resist ance in the main circuit, and by reason of the consequent increase of magnetization of the Held-magnet, and this increase of electro-motive torce in turn increases the encrgy of the held-magnet; but at thesame time the diminution of current in the main circuit diminishes the magnetization ot the regulating-magnet It; hence the iield-of-Iorce tends to be weakened b y the diminished energy ol" the magnet R, and at the same time to be strengthened by increased action ot' the field-magnet proper, whereby an equilibrium ot' eiects is produced and a practically uniform electro-motive force is preserved regardless of the extinction of lights, as last stated; and, conversely, starting with one light in operation, it' additional lights be turned on within the capacity of the machine, then the electro-motive force tends to diminish by reason of diminished resistance and by reason ol" the consequcntlydiminished current energizing the field-magnet, and at the same time tends to increase by reason of the increased magnetization of the magnet It. A like equilibrium of eiiiects is produced and a constant electro-motive force with the same result, as is above stated, and this result follows whatever be the constant speed predetermined, as above described.

By placing the regulating field-magnet in the main circuit with the armature l cause the magnetization ot' both to vary alike, whatever be the variations of resistance in that circuit, and whatever be the speed ot' driving; hence the neutral points of the armature have a constant position, and the position of the brushes need not be changed in order to prevent sparking. It is a well-known fact that in those dynamos whose brushes are normally set with a positive lead the magnetization of the armature tends by its direction to oppose the magnetization ot' the tieldmagnet, while in those dynamos whose brushes are normally set with a negative lead the magnetization of the armature is in such a direction as tends to increase the magnetization of the field-mag net; but in the dynamo which constitutes the present invention this lead is negative, and, accordingly, the magnetization-of the armature assists the magnetization of the Iieldmagnet, and from this fact it follows that in my improved dynamo all variations in the degree ot' magnetization of the armature tend to produce corresponding variations in the magnetization of thegiicld-magnet; hence itis obvious that the self-regulating character of my improved dynamo above set forth is largely, although not wholly, due to the reaction oi' the armature upon the held-magnet in the manner here pointed out. In the case of a separately or permanently excited lield-mag` net the reaction ol the armature upon such magnet is a particularly important i'actor of the described self-regulation.

From the foregoing explanation it is obvious that by means ol` this invention a uniform electro-motive force is preserved, whatever be the number of lights or other resistances in the working-circuit, and whatever be the constant speed of driving, and at the same time any strength ol' current which the armature is capable of carrying can be taken from the con'nnutator by the brushes without sparking; also that this improved dynamo, regarded as a generator, is not self-regulating as against variations of speed.

In the case ol" a dynamo which has a ringarmature the regulatingmagnet affects those armature-coils only which are directly opposite and adjacent thereto, hence it is nccessary i n dynamos of that class to /place a second regulating-magnet upon the opposite side of the armature, as shown in Fig. 2, and in dynamos which have multiple polar armatures additional regulating-magnets are necessary, as shown in Fig. 3. In this ligure it will be understood that G is a generator whose positive and .negative poles are designated by plus and minus signs, respectively.

The foregoing explanation is primarily applicable to a dynamo electric machine regarded as a generator; but by the same mode ot' construction and the reverse mode of operation my improved dynamo beeomes a selfregulating electric motor, which, upon being supplied with a constant electro-motive force, yields a constant speed regardless of variations iu the load which may be placed upon the armature. In the latter case the direction ot' rotation and the position ot' the brushes are the same as in the generator, but the direction of the current through the armature as well as the polarization ot' the regulating lield-1nag net is reversed, as shown in Fig. 3.

In my application No. 136,534, for a patent for a device for preventing sparking in dynamo-electric machines, filed July l, 188i, I have shown a magnet which is adjacent to the armature, butwhich is not strictly a held-magnet, for the reason that the same is productive of no external current or motion. As respects the present application, therefore, I disclaim all electro-magnets which are productive of.

IOO

ITO

no external current in generators, and are prol imitation, substantially as shown, and operatductive of no motion in electric motors, so far as any such magnets are described and claimed in that application. rlhe regulatingmagnet R is a true held-magnet.

I claim as my invention and desire to secure by Letters Patent-g 1. In a dynamo electric machine of that class in which the iicld-magnet proper is not in the main circuit, a regrgulating,` field-magnet located in said circuit and having one of its poles adjacent to that part of the armature which lies between a like pole of said armature and a like pole of the i'ieldmagnet proper ofsuch machine, operating as a generator, and between a like pole of said armature and an unlike pole of said field-magnet proper of such machine, operating as a motor, substantially in the manner and for the purpose specified.

2. In a dynamo-electric machine, whether motor or generator, whose field-magnet proper is separately or permanently excited or is shunt-Wound,a regulating` field magnet wound and connected in series with the armature of such machine and placed with one of its poles adjacent to said armature at a point immediatcly in advance of the like pole of said armature, substantially in the manner and for the purpose specified.

3. A dynamo-electric machine in which the brushes are in a fixed position, and in which an electro-magnet in the Working-circuit of such machine co-operates with the field-magnet thereof` and locates the diameter of coming as described, for the purpose specified.

4. In a dynamo-electric machine, Whether motor or generator, an auxiliary field-magnet consisting of an electro-magnet which is located in the main circuit of the machine and has one of its poles just in advance of alike pole o1' the armature, substantiallyin the manA ner and for the purpose specified.

5. A dynamo-electric machine, whether motor or generator, provided with an auxiliary field-magnet which is attached to the principal field-magnet of such machine, is located in the main circuit, and has a pole slightly in advance of a like pole of the armature, suh stantially in the manner and for the purpose specified.

6. A dynamo-electric or electro-dynamic machine provided with a principal and an auxiliary Iieldanagnet, the latter being an electro-magnet which is wound to a greater electro-magnetic efficiency than the armature of said machine, is placed in the main circuit, au d has a magnetic pole adjacent to a like magnetic pole of said armature, substantially in the manner and for the purpose specified.

In testimony whereol I hereunto set my hand in the presence of two subscribing witnesses.

RXCHARD H. MATHER. I

Vitncsses:

Y/ ILLARD EDDY, MoRcAN WV. Brilon. 

